Japan Aerospace Exploration Agency (JAXA) launched the Advanced Land Observing Satellite-4 (ALOS-4) on July 1st, 2024. The first light images were taken by Phased Array type L-band Synthetic Aperture Radar-3 (PALSAR-3) onboard the ALOS-4 from July 15th to 17th, 2024. PALSAR-3, featuring Digital Beam Forming (DBF) technology, increases observation swath to 200 km with high resolution. This enables both wide-area disaster monitoring and short-term basic observation. The first light image of the Kanto region in Japan, which was successfully taken with a 200 km observation swath with 3 m resolution, clearly demonstrates the advancements from the ALOS-2. The Amazon rainforest in Brazil was also observed, enabling the monitoring of deforestation by comparing the data with observations from the ALOS and the ALOS-2. This long-term time series data of L-band SAR is expected to contribute to global environmental monitoring. The ALOS-4 also supports various observation modes, such as Spotlight mode for detailed monitoring and ScanSAR mode for large-scale monitoring.
